1. A Fast, High Resolution System for Converting 35mm Ophthalmic Slides to Digital Images
M.E. Verdugo1, P. Nadolny1, J. Buonomo1, A. Sasai1, B. Laÿ2, G. Dagniaux2.
1Ophthalmology, Allergan, Inc., Irvine, CA, USA
2ADCIS SA, Herouville-Saint-Clair, France
METHODS
The traditional method for collecting single and stereo-
scopic fundus images is 35mm slides. Life expectancy of
slide films is somewhat limited. This project was initiated to
convert slide film into high quality digital images for future
automated processing/analysis and for long term archival
in a fast, accurate, cost effective, and organized way.
INTRODUCTION
Slide Acquisition: A software engineering effort
was undertaken by Allergan and ADCIS to determine
the optimal solution to convert tens of thousands
35mm slides into high resolution digital images.
This effort led to the development of an innovative
system using a 10.1 mega-pixel digital SLR camera, a
copy-stand, a light box to back-light the slides and a
personal computer controlling the whole system.
Slide Visualization: The Slide-DisplayTM module enables the user to
query the MySQLTM database with advanced selection and filtering tools to
display images and data. The user can adjust image brightness, contrast,
zoom only for improved display with no modification of original data, and
view stereoscopic image pairs using Berezin Screen Vu 3D glasses.
Database indexes can be exported to allow external data sources
reconciliation. The indexes can be edited to correct user data entry errors.
In comparison to a film scanner, our system demonstrated superior image quality, better color
rendering, and minimal noise. Our system exceeded our desired expectation by allowing very fast
and accurate acquisition, improved resolution for future very accurate automated analysis and
complete and detailed indexing of subject information (including observation date). With future
improvement of digital color camera technology, we expect to further enhance image quality and
performance with minor or no upgrade to the software application.
Image quality comparison
between slides images
converted by a Nikon
CoolscanTM Film Scanner
(4000 dpi) versus a
Canon Rebel XTi
digital camera.
CONCLUSION
RESULTS
Scanner vs. Digital Camera
METHODS
The system software developed by Allergan
and ADCIS meets all these requirements. It is
comprised of two main components:
• Slide-SnapperTM - To capture slide images
and patient data; and
• Slide-DisplayTM - To query the database
and display single and stereoscopic
images
Acquisition Workstation
The main system requirements were to provide:
1. Capability to snap two images of a slide:
• A low resolution JPEG image of the frame
(with subject identification), and
• A full resolution, RAW mode image of the
film portion of the slide, later converted to
a TIFF image
2. Detailed index of all images for quick image
filtering and retrieval
3. Full control of the camera settings to ensure
the digitized image maintained the fidelity of
the slide’s image
4. Superior system performance compared to
conventional slide scanners in terms of
speed and image quality
5. Capability to view stereoscopic images in 3D
using appropriate glasses.
6. A specialized calibration protocol to ensure
proper color rendering
Using two of our acquisition
workstations, two trained
users digitized 78,000 slides
during an 81-day period.
With two scanners it would
have taken about 15
months to convert
the same set
of slides.
Image Indexing
Slide Frame Capture
Acquisition Color Control
10.1 Mpixels10.8 Mpixels
Image Size
1.3 slides/minute0.3 slides/minute
Capture Speed
Significant Spectral Noise
on Color Profile
Minimal Spectral Noise
on Color Profile
High Frequency Noise No High Frequency Noise
Slide-SnapperTM